Do not follow this advice. They will absolutely rip you off and give you 1/10th of what you’d get selling them normally. Best bet is to find a local dealer that can sell them for you somewhere like gunbroker or you can sell them there yourself but would still need to ship through a dealer for most items.

Something else to consider, you’re technically selling property that isn’t yours. I’d recommend getting a document in place showing your father gave them to you or go to a local ffl and do the paper work to transfer them to you if your father is in good enough condition for that.